From: lewie <unknown>
Date: Tue, 10 Apr 2001 22:34:47 +0000 (+0000)
Subject: [project @ 2001-04-10 22:34:47 by lewie]
X-Git-Tag: Approximately_9120_patches~2171
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=54cbdfde8ff2073adebea3199efffa79367571ef;p=ghc-hetmet.git

[project @ 2001-04-10 22:34:47 by lewie]
Don't use foldr/build if we've got a parallel list comp.  We'd need to
have/generate a family of functions foldr{2,3,...} to do anything nicer here.
---

diff --git a/ghc/compiler/deSugar/DsListComp.lhs b/ghc/compiler/deSugar/DsListComp.lhs
index 431fb93..337535d 100644
--- a/ghc/compiler/deSugar/DsListComp.lhs
+++ b/ghc/compiler/deSugar/DsListComp.lhs
@@ -44,7 +44,8 @@ dsListComp :: [TypecheckedStmt]
 	   -> DsM CoreExpr
 
 dsListComp quals elt_ty
-  | not opt_FoldrBuildOn 		 -- Be boring
+  |  not opt_FoldrBuildOn 		 -- Be boring
+  || isParallelComp quals
   = deListComp quals (mkNilExpr elt_ty)
 
   | otherwise				 -- foldr/build lives!
@@ -58,6 +59,9 @@ dsListComp quals elt_ty
     dsLookupGlobalValue buildName	`thenDs` \ build_id ->
     returnDs (Var build_id `App` Type elt_ty 
 			   `App` mkLams [n_tyvar, c, n] result)
+
+  where isParallelComp (ParStmtOut bndrstmtss : _) = True
+	isParallelComp _                           = False
 \end{code}
 
 %************************************************************************